1. Field of the Invention
The present invention relates generally to a process for forming a solid hypochlorite precipitate on a fibrous substrate and the formed hypochlorite-releasing substrate. The process for forming a solid hypochlorite comprises the steps of: exposing one or more fibrous materials to an effective amount of aqueous alkaline earth salt solution, treating the fibrous material with an effective amount of hypohalite solution and allowing the alkaline earth salt solution to react with the hypohalite solution to form solid hypochlorite precipitate around the fibers in the fibrous material. The hypochlorite-releasing substrate may have a variety of uses, including but not limited to, cleaning wipes, dishwashing towels for hand use or in dishwashers, toilet bowl cleaning pads, bath and shower cleaning pads, laundry sheets for the washer or dryer, water filters, wound dressing materials, carpet stain removal pads, air deodorizer pads, food freshness substrates, air filtration substrates, and water disinfecting substrates. The composition and process for making the hypochlorite-releasing substrate enables the liquid phase to be removed from the substrate creating a stable hypochlorite-releasing substrate which is capable of rapid release of hypochlorite upon exposure to moisture or liquid.
2. Background of the Invention
There is a need for a stable cleaning and disinfecting substrate, such as a wipe or cleaning article that is capable of cleaning and removing residues from soiled surfaces while simultaneously destroying undesirable microorganisms, e.g. bacteria, mold, viruses, prions and the like that colonize on common surfaces with which people come into contact, such as door knobs, countertops, toilet seats, floors, beds, walls, and the like.
Hypohalite releasing compounds, such as the hypohalite and related compounds that release active forms of hypohalite and/or halogens, are extremely effective disinfectants capable of destroying a wide range of microorganisms. Hypohalite releasing antimicrobial compounds, and in particular the hypohalite, constitute a class of strong chemical oxidants possessing both cleaning and bleaching properties in addition to their antimicrobial properties making them superior to other disinfectants, such as quaternary ammonium biocides. The hypohalite class of chemical oxidants act to rapidly oxidize susceptible substances found in inorganic, organic and biological materials, rendering them more easily removed from surfaces, and in the case of colored or pigmented materials, bleaching them to white or colorless end products resulting in effective cleaning and stain removal from soiled surfaces. Owing to their strong oxidizing capability, hypohalite also posses inherent disinfection properties and additionally possess desirable characteristics including excellent aqueous solubility, mobility and a highly dissociative ionic nature. A further advantage of the hypohalite class with regard to disinfecting, is the speed and efficacy with which they attack microorganisms and either destroy them or render them non-viable following very short contact times. Yet a further advantage of the hypohalite is the wide susceptibility of many different types of microbial pests to their strong oxidizing potential and essentially the absence of any known microbe to develop an effective resistance against the action of these materials.
Typically, microbiologically contaminated surfaces seldom comprise only the microorganisms themselves, but include the presence of soils and other residues, including organic, inorganic and biological residues associated with the source of the microbiological contamination. These residues, including, for example, saliva, bodily is fluids, blood and common soils such as foods, oils and dirt, not only host microorganisms, but can act to shield and protect the microorganisms from the disinfectant action of non-hypohalite disinfectant materials.
One seeming disadvantage of the hypohalite class of materials is their susceptibility to decomposition, including self-decomposition and reactive decomposition owing to the interaction of the hypohalite with the substrates and materials, which they contact during packaging and storage. Particularly in the case of pre-wetted wipes, the disinfecting hypohalite composition is impregnated onto and interacts with the absorbent carrier substrate during storage. Hence, freshly prepared solutions or disinfectant articles utilizing these materials are typically required to ensure adequate activity for ensuring effective disinfection of surfaces. Attempts have been made in the past to provide a convenient disinfectant article by loading a liquid hypohalite solution onto an absorbent substrate such as a wipe. One of the problems with pre-loaded bleach wipes is that they lack sufficient stability to ensure suitable disinfecting efficacy at time of use, particularly following typical storage times and/or less than ideal storage conditions representative of real world environments encountered in the home, office, business, hospital or field where needed.
Another prior art embodiment of hypohalite loaded substrate which has been used previously is a dry substrate which is loaded with a solid hypohalite which is adhered to the substrate using a binder or adhesive agent. The problems with these dry loaded solid hypohalite substrates is that the solid hypohalite may only be loaded on the exterior of the surface of the substrate rather than evenly distributed throughout the substrate, the adhesive agent or binder may interferes with the quick release of the hypohalite, and if the particles size of the solid hypohalite is too large then the release rate may be too slow, but if the particles are too small the particles will fall off the substrate too easily and will not be delivered to the desired point of use.